1. Field of the Invention
The present invention relates to a transmit-receive unit suitable for use in a portable telephone.
2. Description of the Related Art
A prior art transmit-receive unit will be described with reference to FIG. 4. A housing 21 made of a metal plate is shaped like a frame which is open at the top and the bottom and has a storage portion 21b defined by four side walls 21a and installation feet 21c provided at the bottom.
Various electric parts 23 for forming a transmitting and receiving circuit are mounted on both sides of a circuit board 22 which is a printed board, stored in the storage portion 21b of the housing 21 and fixed to side walls 21a.
A pair of covers 24 and 25 are made of a metal plate and the cover 24 is attached to the housing 21 to cover the upper open portion of the housing 21 and the cover 25 is attached to the housing 21 to cover the lower open portion of the housing 21 so as to electrically shield up the inside of the housing 21.
The transmit-receive unit constituted as described above is installed on a mother board 26 in such a manner that the installation feet 21c of the housing 21 are placed on a mother board 26 and soldered to an earth pattern (not shown) provided on the mother board 26 and the covers 24 and 25 are grounded to the earth pattern through the side walls 21a of the housing 21.
However, since the transmit-receive unit of the prior art comprises the housing 21 made from a metal, the weight of the housing is large and the obtained transmit-receive unit for use in a portable telephone which is required to be light in weight becomes heavy.
Further, since the two covers 24 and 25 are used, their assembly is troublesome, thereby reducing productivity and boosting costs.